[PJ]

Technically they're not breaking any rules.. It all depends on your return/exchange policy.

I know that photographers and models will buy clothes/shoes/accessories, wear them for a photoshoot, and return them immediately after.

Stores implement these policies so people don't think too much about impulse purchases.
Customers think that "oh I'll just buy it for now... if I change my mind I'll return it." Of course, more often than not, they just keep it.

So, just think of that as making up for the former.

If you want to lose customers and deal with less hassle, just put up an ALL SALES FINAL sign.